CV for Lars Wirzenius

Lars Wirzenius
(Other contact information available on request.)


I am a computer programmer, since 1984. I am an expert in the Linux environment, and have developed free and open source software for decades. I develop software at all levels, from architectural design down to writing even the lowest level of the code.

I am a Finnish citizen, and communicate fluently in Finnish and English, and also Swedish. I also know a smidgen of German.

Stuff I know very well:

  • The Rust language. I’ve been using it since 2019, and it’s now my default language for all new projects.
  • The Python language. I’ve used Python since 1993, and most of my new code since about 2010 has been written in Python.
  • The C language. I’ve used C since 1987, mainly in various Unix-like environments, though originally on 8086 under MS-DOS, plus a little bit of embedded development. (I don’t know much C++.)
  • Linux in general, and the Debian distribution in particular.

I always have several hobby open source projects going on. A selection is at the end of this CV.

Experience and training

UpCloud 2023-: I help maintain the backend software stack and improve development processes and practices.

Consulting 2021-: Self-employed consultant, contractor, and trainer. I have worked on the Sequoia-PGP project, improving the command line tool sq. I give training courses in the basics of the Rust language.

Wikimedia Foundation 2018-2021: Senior software engineer in the Release Engineering team, doing deployments, and maintaining deployment tooling.

QvarnLabs Ab 2016-2018. Co-founder, CTO and software architect. QvarnLabs developed Qvarn and Qvisqve, which provide access-controlled storage of structured data for privacy sensitive applications (see GDPR), and authentication for HTTP APIs (OAuth2, OpenID Connect). Both are open source software, though no longer maintained, after QvarnLabs went bankrupt.

Suomen Tilaajavastuu 2014-2016. Software architect, web services backend (Qvarn).

Codethink 2011-2014. I served in a variety of roles, including technical lead, architect, and developer, for Baserock (, a new way of building and developing embedded and appliance Linux systems. Baserock is open source.

Consultant 2005-2011. I’ve worked on variety of projects for several clients, mainly on open source projects, such as Debian. In 2005-2006 I was under contract to improve the technical quality of the Debian Linux distribution, and as part of that work developed piuparts (, a tool for verifying that Debian packages be installed, upgraded, and removed without problems. Piuparts is open source. I also analyzed bug reports and fixed bugs.

  • Canonical, 2007-2009. I contracted to Canonical, Ltd. to develop the Ubuntu Linux operating system.

  • Catalyst IT, New Zealand, 2010. Contract work on Koha, an open source integrated library management system. I helped with automated testing, and made Debian packages of the software.

Collabora Ltd 2011 I helped a client package some of their internal things for the MeeGo mobile platform. Was let go because client decided to not do MeeGo stuff anymore.

Branchable 2010-2020. This is a blog/wiki/website hosting service built on top of ikiwiki, together with Joey Hess. The entire stack is open source. This was a side project.

Obnam 2006-2017, 2020-. I wrote a backup application and attempted to start a business providing backup services. The business didn’t succeed, but I’ve maintained the software as a hobby, because it’s a fascinating technical problem.

Oliotalo 2002-2004. Oliotalo developed applications for machine to machine communication and telemetry (“IoT” is the modern term): embedded computers are attached to vehicles, waste collectors, or other such machines, get data from various sensors, and communicate wirelessly with a server. I designed and co-implemented the embedded Lisp interpreter, Hedgehog, with which the embedded computers were programmed in Oliotalo projects. Hedgehog was released as open source, but its website no longer exists., 2001-2011 A shell-server ISP on the side.

Akumiitti Telematics / Keko Technologies 2001-2002. Keko developed a platform for machine to machine communication. I designed and implemented the client-side embedded application platform.

Wapit Ltd 1999-2001. I was project and team leader, and chief architect for the Kannel SMS and WAP gateway. Kannel is an open source, multi-threaded, multi-process server that can handle high traffic loads. I was responsible for architectural design, implementation, and project management. Wapit went bankrupt, but Kannel is still in production use worldwide.

Helsinki University of Technology / CS laboratory / HiBase project 1997-1999. HiBase was a research project to develop a main memory database and functional programming language. I wrote C code and did some Linux system administration. HiBase was released as open source.

Debian project, 1996-2018. I helped develop and maintain the free Debian Linux-based operating system as a hobby. I packaged various software, and helped test packages, and in general helped where I could.

University of Helsinki / Department of Computer Science 1993-1996. I was a teaching assistant, helping students with homework and checking their answers. I gave one full course on C programming.

University of Helsinki / Department of Computer Science 1988-2002. Student, part-time studies from 1993 forward on account of working full time. Not graduated.

Selected writing

Select free and open source software projects